Cell Cycle Notes PDF

# Cell Cycle Notes ## EQ: How do cells grow and replace old cells? ## Learning Target: ## Cell Cycle Overview 1. **Interphase** - normal cell activities (time between cell division) - Growth promotion - a group of genes called proto-oncogenes promote cell growth and movement toward cell div...

# Cell Cycle Notes ## EQ: How do cells grow and replace old cells? ## Learning Target: ## Cell Cycle Overview 1. **Interphase** - normal cell activities (time between cell division) - Growth promotion - a group of genes called proto-oncogenes promote cell growth and movement toward cell division throughout Interphase. - Checkpoints - a group of genes called tumor suppressor genes make proteins that "check" the cell to make sure it is healthy enough to move onto the next phase in the cell cycle. - If the cell passes the check point, it continues onto the next phase in the cell cycle. - If the cell fails the check point, other proteins may repair damages within the DNA or the cell may undergo apoptosis (programmed cell death). 2. **Cell Division** - Mitosis - process of producing two genetically identical cells. - Cytokinesis - splitting of cytoplasm once two nuclei have formed. ## Purposes of Cell Division: - Growth - Repair - Maintenance - Reproduction of unicellular organisms ## Interphase - DNA from mom + DNA from dad = Your DNA - Centrioles ## Summary of phases: - Cell grows and does normal cell activities (protein synthesis, ex. breathing, cellular respiration, etc.) - Diploid cell = Cell with 2 sets of DNA (1 mom, 1 dad). - DNA in chromatin form. - During S phase of Interphase: DNA Replication. ## Mitosis - Prophase - Spindle Fibers - Centrioles - 1 Chromosome made of 2 sister Chromatids ## Summary of phases: - DNA coils into chromosomes (each made of two sister chromatids). - Centrioles separate and spindle fibers form - Nuclear envelope begins to disappear. ## Mitosis - Metaphase - Chromosomes made of two sister chromatids line up on spindle fibers at the metaphase plate (middle of the cell). ## Mitosis - Anaphase - Spindle fibers pull chromatids to opposite sides of the cell. ## Mitosis - Telophase - Nuclear envelope begins to reappear. - Spindle fibers and centrioles disappear. - DNA begins to uncoil back to chromatin form. - Cytokinesis occurs via a cleavage furrow in animal cells. ## Final Product ## Summary: - Two new daughter cells have been formed. - Each are genetically identical to the parent cell (and each other). ## Practice: | Organism | Diploid # of Chromosomes | # of Chromosomes at beginning of Mitosis | # of strands of DNA at beginning of Mitosis | # of daughter cells produced after cell division | # of chromosomes in each daughter cell | # of strands of DNA in each daughter cell | Daughter Cells: genetically identical or different? | |---|---|---|---|---|---|---|---| | Example Cell | 4 | 4 | 8 | 2 | 4 | 4 | Identical | | Human | 46 | 46 | 92 | 2 | 46 | 46 | " | | Duck | 80 | 80 | 160 | 2 | 80 | 80 | " | | Newt | 24 | 24 | 48 | 2 | 24 | 24 | " | ## Plant Cell Division The cell cycle is virtually the same for plant cells as it is for animal cells except during Telophase & Cytokinesis. Because plant cells have a cell wall, the cell creates vesicles containing molecules that make up the cell wall and send them to the middle of the dividing cell. Those vesicles then fuse and form a new cell wall, dividing the original cell in two. Whereas, animal cell cytokinesis actually pinches the cytoplasm and cell membrane into two separate cells. - Anaphase - Telophase - Cytokinesis ## Prokaryotic Cell Division - Binary Fission 1. Duplication of chromosome and separation of copies. 2. Continued elongation of the cell and movement of copies. 3. Division into two daughter cells.